This invention relates generally to cutting tool holders and particularly to an adjustable cutting tool holder or assembly for automatic cutting machines, such as screw machines.
Automatic cutting machines are used to cut and form various precision products and product parts used, for example, in medical or telecommunications instruments. The use of precision boring bars or other adjustable cutting inserts to manufacture such products or parts require fine tolerances of up to 0.0005 inches. A typical screw machine uses a cutting tool or knee tool holder which has slots wherein a tool having a carbide or high speed steel cutting member or insert is fixed. The cutting tool is brought into position with respect to a metal workpiece, for example, which is rotated on a lathe mechanism so that the workpiece can be cut and machined accordingly. The position of the cutting members with respect to the workpiece can be moved by either moving the entire holder or by moving the tool within the holder slots.
The principle limitations of prior art or existing cutting tool holders are that they are difficult to adjust and such adjustment cannot be accomplished with precision. The prior art primarily shows unitary block structures which have no adjustable features and which require the use of a hammer or other device to tap either the tool relative to the holder or the holder base relative to the machine turret for positioning purposes. Thus, the tool holder itself is loosened, tapped with a hammer, for example, and then retightened or alternatively, clamping means on the holder are loosened and the cutting member is moved with respect to the holder slot and then retightened. In view of the precise tolerances required for most cutting purposes, this process is laborious, time consuming and imprecise.
The cutting tool holder of this invention is an adjustable assembly utilizing adjustment means to position a cutting tool with respect to a rotated working piece. The adjustable cutting tool holder has a base portion and an adjustable block or holder portion united by an adjusting mechanism. This adjustable structure eliminates the requirement of tapping the tool holder or cutting tool with a hammer for proper adjustment of the cutting tool, and provides an easy and precise means to accurately position the cutting tool with respect to the workpiece.